1. Technical Field
The invention may include embodiments that relate to a composition including a sulfur-functional linear polyorganosiloxane having chemically-protected sulfur groups. The invention may also include embodiments that relate to a method of making and using the sulfur-functional linear polyorganosiloxane in elastomer compositions.
2. Discussion of Related Art
Natural or synthetic rubbers (or elastomers) in their unvulcanized state may have inherently low mechanical properties that may prevent them from being used in applications requiring high tensile strength. The elastomer may need to be chemically crosslinked (vulcanized) to maximize the modulus and tensile properties. Elemental sulfur may be used as a “primary” crosslinking agent to vulcanize natural or synthetic rubbers.
Additional crosslinking agents such as mercaptosilanes may also be used to provide secondary crosslinking with the elastomer. The mercaptosilanes may also be used as compatibilizers for rubber compositions comprising reinforcing fillers. However, mercaptosilanes may have high chemical activity and may prematurely cure with the elastomer (scorch) during compounding of the rubber formulations. This scorching reaction may cause undesirable increase in viscosity and less than desirable filler dispersion resulting in poor processability and low reinforcing action.
It may be desirable to have sulfur-containing secondary crosslinking agents that may not prematurely cure with the elastomer and may also function as compatibilizers for fillers, when so desired. It may be desirable to have vulcanized rubber compositions with properties other than those currently available for varied applications.